Compensating for an antenna that is close enough to a touchpad to cause interference with touch sensor operation

Abstract

A touch sensor that can operate normally while located within a distance that would otherwise cause an antenna used for communication with a contact less smart card to interfere with operation of the touch sensor by providing a means for the touch sensor to compensate for the interference caused by the antenna.

1 . A method for operating a touch sensor that is in proximity of an antenna that can interfere with operation of the touch sensor, said method comprising the steps of:
 1) providing a touch sensor including an electrode grid disposed on a first substrate, and touch sensor circuitry for receiving signals from the electrode grid and detecting a pointing object that is touching a surface of the touch sensor;   2) providing an antenna for communicating with a contactless card reader;   3) disposing the antenna in a location that when used may cause interference with operation of the touch sensor;   4) providing a first set of compensation data that is used by the touch sensor circuitry when the antenna is on; and   5) accurately determining a location. of the pointing object on the surface of the touch sensor when the antenna is on by using the first set of compensation data.   
     
     
         2 . The method as defined in claim.  1  wherein the method. further comprises the steps of:
 1) providing a second set of compensation data that is used by the touch sensor circuitry when the antenna is off; and 
 2) accurately determining a location of the pointing object on a surface of the touch sensor when the antenna is off by using the second. set of compensation data. 
 
     
     
         3 . The method as defined in  claim 1 . wherein the step of proving the antenna further comprises the step of providing a near field communication (NFC) antenna. 
     
     
         4 . The method as defined in  claim 1  wherein the step of providing the touch sensor further comprises the step of providing a capacitance sensitive touch sensor. 
     
     
         5 . The method as defined in  claim 1  wherein step of providing a touch sensor that can detect the pointing object in contact with the surface of the touch sensor further comprises the step of providing a touch sensor that can perform proximity detection of the pointing object when the pointing object is near the touch sensor. 
     
     
         6 . The method as defined in  claim 1  wherein the step of using a first set of compensation data when the antenna is on further comprises the step of the touch sensor circuitry receiving a signal from the antenna circuitry that indicates a mode of operation of the antenna so that the correct set of compensation data is used. 
     
     
         7 . The method as defined in  claim 2  wherein the step of providing a first set of compensation data that is used by the touch sensor circuitry when the antenna is on further comprises the step of dynamically updating the first or the second set of compensation data if the operating environment changes, to thereby enable the touch sensor and the antenna to continue to operate in a changing operating environment. 
     
     
         8 . The method as defined in  claim 7  wherein the step of dynamically updating the first or the second set of compensation data if the operating environment changes further comprises the step of updating the first or the second set of compensation data when there is a substantial change in temperature or humidity sufficient to change operation of the touch sensor or the antenna. 
     
     
         9 . A touch sensor system that operates accurately when in proximity of an antenna that can interfere with operation of the touch sensor, said system comprised of:
 a touch sensor having a touch surface, and including an electrode grid disposed on a first substrate;   an antenna for communicating with a contactless card reader, wherein the antenna is disposed in a location that when used may cause interference with operation. of the touch sensor; and   touch sensor circuitry for receiving signals from the electrode grid and detecting a pointing object that is in contact with the touch surface, wherein the touch. sensor circuitry uses a first set of compensation data that compensates for the antenna when the antenna is on and accurately determines a location of the pointing cot.   
     
     
         10 . The system as defined in  claim 9  wherein the system further comprises a second set of compensation. data that is used by the touch sensor circuitry when the antenna is off to thereby accurately de ermine a location of the pointing object on the surface of the touch sensor. 
     
     
         11 . The system as defined in  claim 9  wherein. the antenna is a near field communication (NFC) antenna. 
     
     
         12 . The system as defined in  claim 9  wherein the touch sensor further is a capacitance sensitive touch sensor. 
     
     
         13 . The system as defined in  claim 9  wherein the touch sensor also performs proximity detection of the pointing object.